Heat treating razor blade strips



Sept. 22, 1931. T. C.-SHEEHAN 1,824,410

HEAT TREATING RAZOR BLADE STRIPS Filed July 12. 1929. 6 Sheets-Sheet 1TTORNEY Sept. 22, 1931.

T. c. SVHEEHAN HEAT TREATING RAZOR BLADE STRIPS 6 Sheets-Sheet 2 FiledJuly 12. 1-925 fmzy TOW.

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Sept. 22, 1931.

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HEAT TREATING RAZOR BLADE STRIPS Filed July 12. 1929 6 Sheets-Sheet 5 Or LIES $12 I T 11 r g a i :1 I i;

J L i 2 Sept. 22, 1931. T. c. SHEEHAN HEAT TREATING, RAZOR BLADE STRIPSFiled July 12. 1929 6 She ts-Sheet 4 M ATTORNEY INVENTO .Lu .rLl .8.

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HEAT TREATING RAZOR BLADE STRIPS Filed July 12. 1929 6 Sheets-Sheet 5ATTORNEY I 7! v Q I LVNTOR p 1931. w T. c. SHEEHAN 1,824,410

HEAT TREATING RAZOR BLADE STRIPS Filed July 12. 1929 6 Sheets-Sheet 6 rA FL OR M distribute the Patented Sept. 22, 1931 UNITED STATES PATENT;OFFICE THOMAS C. SHEEHAN, OF UPPER MONTCLAIR, NEW JERSEY, ASSIGNOR TDURH'AM DUPLEX RAZOR COMPANY, A

CORPORATION OF NEW YORK HEAT TREATING RAZOR BLADE STRIPS Applicationfiled July 12,

This invention relates to heat treating metal strips, particularly thinsteel strips such as those from which safety razor blades are formed.The present invention is particularly applicable, the production ofsafety razor blades which are very hard at the edges, and consequentlvhold their edge well, and yet soft at the center so that they are notliable to break when bent to fit a curved holder, as are blades whichare made hard throughout.

It is one of the principal objects of the invention to provide a heattreating method.

and apparatus applicable to the rapid and economical production of suchblades. To this end it is an object of the invention to provide forcontinuously heat treating a traveling thin steel strip prior to cuttingto blade lengths, to uniformly temper such blades at low cost. Anotherobject is to provide a method and means for drawing the temper fromstrip so that articles cut therefrom will be hard where hardness isdesirable and relatively soft where brittleness is objectiohable. Otherobjects are to dispense with troublesome fluid baths,-to provideefficient cooling or quenching means operating through surface contactwith the strip, and in such means to wear and heating effect of thestrip over a wide area. With these and other cally mentioned in view,the invention consists in certain constructions and combinations whichwill be hereinafter fully described and then more; particularly pointedout in the claims.

In the accompanying drawings which 7 form a part of this specificationand in which like characters of reference indicate the same or likeparts? Fig. 1 is a side elevation of a machine constructed in accordancewith theinvention with a portion of the furnace broken away; Fig. 2 is arear elevation of the machine shown in Fig. 1;

Fig. 3 is a plan view of. the machine shown in Fig. 1;

Fig. 4 is an enlarged detail plan view, partthough not limited to,.

a selected portion of a tempered objects not specifi- 1929. Serial No.377,695.

ly-broken away, of a portion of the machine shown in Fig. 1;

Fig. 5 is a vertical longitudinal section taken on the line 5-5 of Fig.4;

Fig. 6 is an enlarged detail plan View of the furnace shown in Fig. 1with the top plates removed Fig. 7 is a vertical section of the furnacetaken on the line 7-7 of Fig. 8;

Fig. 8 is a cross section of the furnace taken on the line 8-8 of Fig.6;

Fig. 9 is a detail view of the exit end of the furnace taken on the line9--9 in Fig. 5.

Fig. 10 is a detail perspective view of one of the guides shown in Fig.1;

Fig. 11 is an enlarged detail elevation,'-partly in section, Fig. 1;

Fig. 12 is a plan view of the cooling device;

Fig. 13 is an end view of the device shown in Fig. 11;

Fig. 14 is a vertical cross section through the temper drawing mechanismshown in Fi 1;

Fig. 15 is a plan view of the exit end of the temper drawing mechanismtaken on the line.

1515 in Fig. 5;

Fig. 16 is a detail plan view of the razor blade strip; Fig. 17 is adiagrammatic cross section of the razor blade strip shown in Fig. 16;and

Fig. 18 is an enlarged detail view of a portion of the mechanism shownin Fig. 14.

The apparatus used in carrying the invention into effect comprisesmechanism for'feeding a metal strip, means for tempering the strip as itis fed, and devices operating on the strip fed from the tempering meansto draw the temper from a selected portion thereof in of the coolingdevice shown in.

order to produce a strip which is hard where yet relatively soft In thehardness is desirable and p where brittleness is objectionable.

'best constructions, the tempering means includes a furnace designed touniformly heat the strip and a combined guide and flame ofreciprocatingcooling surfaces are provided engaging opposite sides ofthe strip. In the best constructions also, said devices include a hotsurface contacting a selected portion of the strip. The method utilizedin carrying out the invention consists in imparting feeding movement tothe strip, then heating and rapidly cooling the strip to temper the sameand passing a selected portion only of'the cooled strip into contactwith a hot surface to draw the temper of that portion of the strip, tomake the strip relatively soft and flexible at that part. The abovemeans and method may be widely varied in practice within the scope ofthe claims, for the particular structure and method selected toillustrate the invention is but one of many possible concreteembodiments of the same. The invention, therefore, is not to berestricted to the precise details shown and described. 1

Referring to the drawings, the device selected to illustrate theinvention consists generally of a furnace F through which the strip ispassed from left to right, a cooling or quenching device G into whichthe heated strip passes and in which it is rapidly cooled or chilled togive the strip a hard temper, a temper drawing device D into which thetempered and cooled strip in which a selected portion thereof isreheated to draw the temper of that portion of the strip, and stripfeeding means R which serves to continuously draw the strip through thepreceding mechanism.

The strip S from which, in'the present embodiment, razor blades are tobe subsequently formed, is fed up a guideway 19 (Fig 1.) and into thefurnace F which consists of a trough shaped outer casing 20 carried on atable 22 constituting the base for several parts of the machine, havinga fire-brick lining 25, and closed at the top with a refractory topplate 24. A series of projecting fire bricks 26 serve to support a pairof oppositely disposed longitudinal guides 28 extending into and throughthe furnace and provided with opposed pairs of bosses 30 and 31 andgrooves 32 receiving the edges of the strip. The bosses which arearranged at intervals alon the length of the guides, serve to support anguide the central portion of the strip, while permitting free access ofthe heat of the furnace, to prevent curling or bending thereof, whilethe grooves at the edges support the edge portions of the strip.

, In order to uniformly heat the strip S as it is fed through thefurnace, a series of gas nozzles 35 on either side of the furnace arearranged at equal distances from each other lengthwise of the furnaceand are also equally spaced from the sides of the guides 28 remote fromthe strip. Thus the guides Will serve to bafile the flame, in order toprevent burning of the thin strip, by the direct action from the gasflames on the strip. The strip then passes out of the furnace at theexit end, closed by an apertured plate of refractory material 36.

To rapidly cool or quench the heated strip in order totemper the stripto hardness (in the present instance to'the hardness desirable for thecutting edges of razor blades), the strip is passed betweenreciprocating cooling surfaces 40 and 41 of the temper drawing device C.These surfaces are formed on a pair of tanks 42 and 43 and are mountedfor reciprocation across the faces of the traveling strip on thetransverse guide rails 44 and 45 by means of bored lugs 47 and 48respectively.

To regulate the pressure under which these cooling surfaces engage theopposite faces of the strip, the guide rails 44 are supported formovement toward and away from the guide rails 45 by bosses 50 at eitherend of these rails, carried by slides 51 in guides 52 and held againstlateral movement by cap screws 53 in vertical slots 54 of the slides 51.These cap screws are secured in a pair of brackets 55 whichconstitutethe main support for the cooling device C. Thus the weight of the uppercooling tank and supporting rails rest on the face of the strip pressingit against the strip of the lower cooling tank. This pressure isaccurately regulated by means of screws 56 adjustable in lugs 57 onbrackets 55 and supporting at their upper ends springs 58 bearing on thelower side of the slide 51. Thus movement of the screw upward woulddecrease the pressure of the cooling surface on the strip, and downwardwould increase said pressure.

For inspection and in emergencies, the cooling surfaces are quicklyspread apart by means of the hand lever 61' secured to rock shaft 62 onwhich is fixed a pair of cranks 63 connected by links 64 with cross bars65 connecting the guide rails at each end. The reciprocating -motion ofthe tanks 42 and 43 relative to the strip is produced by a walking beam66 connected at one end by link 67 to upper tank 42 and at the other endby link 68 tothe lower tank 43 and pivoted at its center with one of thebrackets 55 by lugs 69 and the pivot pin 70 extending therethrough. Thewalking beam 66 is oscillated by a link 71 connected to its lower endand operated by a crank 72 on a shaft 73 of reducing gear 74 driventhrough a chain drive 75 from the main shaft 76 of the machine The'tanks42 and 43 which are provided with a series of bafiles 80 and 81 todistribute the flowof cooling liquid therein and thus uniformly cool thesurfaces engaging the strip, aresupplied with cooling liquid, ordinarilybrine, through flexible pipes 82 connected to suitable supply anddischargepipes 83 and 84. Thus the strip as it passes through thecooling device C is rubbed across its faces at a regulated pressure byever changing uniformly cooled surfaces,- whereby the wear and heatedeffect caused by the strip is evenly distributed over the coolingsurfaces.

The cooled and tempered strip then passes into the temper drawing deviceD through the apertured insulating block 90. This device consists of aheated metal block or anvil 91having a narrow rib 92 extendinglongitudinally of the strip and having an upper horizontal face 93engaging a selected portion of the strip from which it is desired todraw the temper, which, as illustrated, is the central portion of, thestrip which will afterwards form the central bent portion of razorblades formed from the strip. This surface is indirectly heated by meansof gas nozzles.

94 directed upwardly from either side of the block 91 against itsunderside or bottom surface. The heat is confined to the block-bysuitable furnace construction, such as an outer casing 96, a refractorylining 97, and a refractory perforated top plate 98.' The centralportion of the strip is held against the surface 93, and upward curlingof the strip (to which such a strip has a tendency when heated on oneside) prevented by a series of rollers mounted at intervals along theupper face of the strip by means of pins 101' and a bar 102 secured toan arm 103 pivotedon an axis 104 parallel to the strip in a bracket 105.The weight of the bar 102 and arm 103 is made such that the rollers 100act on the strip with a predetermined pressure found suitable for thispurpose. The strip as it passes from between the surface 93 and therollers 100 will be very hard at the edges but soft, and therefo'reeasily bendable without danger of breaking at the center.

The strip now passes between the friction rollers and 111 of the stripfeeding device R which, in the construction shown, is continuouslydriven to draw the strip through the several devices already described.The upper roller 110 is pivoted on a head block 111a which is movable upand down by ascrew 112 so as to adjust the pressure of the rollers. Theshaft 115 of'the lower roller is driven from the main shaft 76 of themachine, by means of a coupling 116, a gear 117 on the roller shaft 115engages a gear 118 on the shaft 119 of the upper roller 110. The rollershafts 115 and 119 are supported in a pair of .brackets 120 mounted onthe table 22. The main I shaft 76 of the machine is suitably driventhrough the reduction gearing 121 and pulley 122 and belt 123 from; amotor 124.

What is claimed is:

1. The combination with mechanism for feeding a metal. strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the mid por-' tionthereof only.

2-. The combination vith mechanism for feeding a metal strip/of meansfor tempering the strip as it is, fed, and devices operatincluding afurnace means to draw the temper from the mid portion thereof onl saidmechanism operating to feed the metal strip continuously.

3. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the mid portionthereof only, including an elongated furnace having a series of gasnozzles on either side of said strip, of said strip and equally spacedfrom said strip and each other to uniformly heat the strip. e

4. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and-devices operating on the stripfed from the tempering means to draw the temper from the mid portionthereof only, cludinga furnace and a guide for said strip extendingthrough said furnace.

5. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the mid portionthereof only,

and a combined guide and flame baflle for through said furnace.

6. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from. the mid portionthereof only, said tempering means including a cooling surfacecontacting the strip.

7. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the strifed from the tempering means to draw the temper from the strip, saidtempering means including a horizontally moving cooling surfacecontacting said stri 4 8. The combination with mechanism for feeding ametal strip, of means for tempering the strip as it is fed, and devicesoperating on the strip fed from thetempering means. to draw the temperfrom the strip, said tempering means including horizontallyreciprocating cooling surfaces engaging opposite said tempering meanssaid tempering means said nozzles being arranged lengthwise saidtempering means inv said strip extending 10. The combination withmechanism for feeding a metal strip, of means for tempering the strip asit is fed, and devices operating on the strip fed from the temperingmeans to draw the temper from the strip, said tempering means includinga tank for cooling liquid having a surface engaging said strip and meansfor reciprocating said tank horizontally to cause relative movement ofsaid surface and said strip.

11. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the strip, saidtempering means including cooling surfaces be tween which the strip isfed, slides connected to one of said cooling surfaces, springssupporting said slides, and means for adjusting the pressure of saidsprings for regulating the pressure with which said cooling surfacesengage the strip. J-

12. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the mid portionthereof only, said devices including a hot surface contacting saidportion of the strip.

13. The combination with mechanism for feeding a metal strip, of'meansfor tempering the strip as it is fed, and devices operating on the stripfed from the tempering means to draw the temper from the mid portionthereof only, said devices including a metal block having a surfaceengaging the selected portion of the strip and means for indirectlyheating'said surface by heating an-- other portion of said block.

14. The combination with mechanism for feeding a metal strip, of meansfor tempering the strip as it is fed, and devices operat ing on thestrip fed from the tempering means ing baflies foruniformly distributingthe cooling liquid therein.

18. The method of heat treating thin steel strips which consists inimparting feeding movement to the strip, then heating and rapidlycooling the strip to temper the same and passing the mid portion only ofthe cooled strip into contact with a hot surface to draw the temper ofthat portion of the strip.

19. The method of heat treating thin steel strips which consists inimparting feeding movement to the strip, then heating and rapidlycooling the strip to temper the same and passing the mid portion only ofthe cooled strip into contact with a hot surface to draw the temper ofthat portion of the strip, said cooling step consistin in rubbing a coldsurface across the face 0 the strip.

In testimony whereof, I have signed my name to this specification.

THOMAS C. SHEEHAN.

.to draw 'thetemper from the mid portion thereof only, said devicesincluding a hot surface on which said strip rests and a series ofrollers pressing on the other side of said strip. 7 v

15. Means for rapidly and uniformly cooling a traveling metal stripcomprising oppo-' sitely disposed cooling surfaces engaging oppositesides of said strip, and means for imparting to said surfaces movementtrans verse-to that of said strip. 16. Means for rapidly cooling atraveling strip comprising a tank for cooling liquid having a surfaceengaging a face of said strip,

and means for moving said tank transversely relative to said strip.

17; Means for rapidly cooling a traveling strip comprising a tank forcooling' liquid having a surface engaging a face of said strip, andmeans for moving said tank transversely relative to said strip, saidcooling tank hav-

